This paper gives the results of a dynamical analysis of the Globesat gravity gradient stabilized satellite in a 500 km circular orbit. The linearized equations of motion are developed and the stability of the satellite is investigated. The satellite is equipped with magnetic torquers for the purpose of providing attitude correction torques. These correction torques can be used to effect large c...

Attitude data, which is the important data strongly correlated with the geometric accuracy of optical remote sensing satellite images, are generally obtained using a real-time Extended Kalman Filter (EKF) with star-tracker and gyro data for current high-resolution satellites, such as Orb-view, IKONOS, Quickbird,Pleiades, and ZY-3.We propose a forwardbackward Unscented Kalman Filter (UKF) for po...

Abstract— In response to the interest to re-use Palapa B2R satellite nearing its End of Life (EOL) time, an idea to incline the satellite orbit in order to cover a new region has emerged in the recent years. As a prolate dual-spin vehicle, Palapa B2R has to be stabilized against its internal energy dissipation effect. This work is focused on analyzing the dynamics of the reusable satellite in i...

Communication via satellite begins when the satellite is positioned in the desired orbital position. Ground stations can communicate with LEO (Low Earth Orbiting) satellites only when the satellite is in their visibility region. The ground station’s ideal horizon plane is in fact the visibility region under 0 ̊ of elevation angle. Because of natural barriers or too high buildings in urban areas,...

There is a substantial amount of literature within the field of spacecraft control which deals with the separate issues of position and attitude control; comparatively little work has been carried out on the joint nonlinear problem of spacecraft position and attitude control. (R.Pongvthithum etal 2005, H.Wong etal 2001, S.M.Veres etal 2002) provide control solutions for spacecraft position cont...

The Polar BEAR satellite was launched successfully from Vandenberg Air Force Base, Calif., in November 1986. A Scout launch vehicle placed Polar BEAR into a circular, polar orbit at an altitude of lcxx) kIn. The satellite's four instruments are designed to yield data on RF communications, auroral displays, and magnetic fields in the earth's polar region. The Polar BEAR attitude control system i...

SNAP-1 is a low-cost nanosatellite build by Surrey Satellite Technology Ltd. (SSTL), it is amongst other objectives a technology demonstrator for 3-axis stabilisation and orbit control for a future constellation of small satellites during formation flying. The satellite uses a single miniature Ymomentum wheel, 3-axis magnetorquer rods and a single butane gas thruster to ensure a nominal nadirpo...

This paper presents an anlysis based on the momentum conservation equations of a redundant free-flying spacecraft/manipulator system, acting in zero-gravity environment. In order to follow a predefined end-effector path, the inverse kinematics at velocity level is considered. The redundancy i solved alternatively in terms of pseudoinverses and null-space components of the manipulator inertia ma...

The paper outlines orbit and attitude control problems of a long-distance two-satellite drag-free formation for the Earth gravity monitoring. Modeling and control design follows the Embedded Model Control and shows how disturbance dynamics and rejection are mandatory. Orbit and attitude control can be treated separately except in the thrust dispatching law of the all-propulsion actuation. Orbit...